The seven galaxies highlighted in this new image from the NASA/ESA/CSA James Webb Space Telescope have been confirmed to be at a distance that astronomers refer to as redshift 7.9, which correlates to 650 million years after the Big Bang. This makes them the earliest galaxies yet to be spectroscopically confirmed as part of a developing galaxy cluster.
Galaxy clusters are the greatest concentrations of mass in the known Universe, which can dramatically warp the fabric of spacetime itself.
This warping, called gravitational lensing, can have a magnifying effect for objects beyond the cluster, allowing astronomers to look through the cluster like a giant magnifying glass.
Dr. Takahiro Morishita, an astronomer at the IPAC-California Institute of Technology, and colleagues were able to utilize this effect, looking through Pandora’s Cluster (Abell 2744) to view a protocluster in the early Universe.
“This is a very special, unique site of accelerated galaxy evolution, and Webb gave us the unprecedented ability to measure the velocities of these seven galaxies and confidently confirm that they are bound together in a protocluster,” Dr. Morishita said.
“The precise measurements captured by Webb’s Near-Infrared Spectrograph (NIRSpec) were key to confirming the galaxies’ collective distance and the high velocities at which they are moving within a halo of dark matter — more than about 1,000 km per second (2 million mph).”
The NIRSpec spectral data allowed the astronomers to model and map the future development of the gathering group, all the way to our time in the modern Universe.
The prediction that the protocluster, named A2744-z7p9OD, will eventually resemble the Coma Cluster means that it could eventually be among the densest known galaxy collections, with thousands of members.
“We can see these distant galaxies like small drops of water in different rivers, and we can see that eventually they will all become part of one big, mighty river,”…
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